Treatment of gasoline



i Dem 1942 ATENT OFFICE;

l 1 ATMENT or GASOLINE Joseph A. Chenicek, fihicago, 111., assignor to Universal Oil Products Company, Chicago, 111., a corporation of Delaware No Drag. Application February 29, 1940, Serial No. 321,575

16 Claims.

This invention relates to a method for improv-- ing the stability of hydrocarbon distillates insofar as color and gum formation are concerned. More particularly the process concerns improved methods of preventing deterioration of cracked gasolines which may be stored over relatively long periods of time in the presence of air.

The use of inhibitors to prevent the depreciation of olefin-containing hydrocarbon distillates such as cracked gasoline has been practiced. Such compounds as alkyl-substituted phenols,

aminophenolsf-fractions of wood tar distillates, etc., have been added to cracked gasoline in relatively minor quantities, of the order of twill-0.1% to inhibit the formation of objectionable oxidation products and prevent loss of color and antiknock properties of said gasoline during storage periods. The use of inhibitors has replaced or supplemented such forms of refining as acid-treating, clay-treating and the like. The

result has been a material saving in refining costs as well as the conservation of substantial amounts of gasoline which were formerly lost in the refining steps.

The present invention offers a means of improving the inhibiting properties of gasoline inhibitors and of effecting material savings in the quantities of such materials which may be required adequately to preserve the valuable propwhereinR may be a hydrogen atom or may comprise an amino alkyl group, R is an amino alkyl group and m is an integer. Representative compounds are diethylene triamine, triethylene, tetramine, tetraethylene pentamine, etc.

The present class of compounds are used in combination with recognized gasoline gum inhibitors such as N-substituted alkyl amino phenols, alkyl phenols, substituted phenol others, fractions of wood tar distillate and others.

The compounds of this invention may be added to the gasoline separately or simultaneously with the gum inhibitor, or may be mixed with the gum inhibitor and the mixture added to the gasoline.

The quantity of the amino-alkyl-substituted alkylene diamine which is commonly used in gasoline is of the order of 0.000'1-0.0l% by weight of the gasoline. The exact quantity required is a function of the inhibitor with which it is used and thegasoline to which his added, and is directly dependent upon the desired stability of thegasoline. In any event, the total weight of the inhibitor plus the amino alkyl-substituted diamine to yield a given storage stability as indicated by the oxygen bomb induction period is less than the corresponding amount of the inhibitor alone to give the same induction period. The compounds of this invention are not of themselves gasoline gum inhibitors and the effect observed is not the additive efiect whichmight be expected by the joint use of two known gum When the compounds are added alone to cracked gasoline in amounts up to apinhibitors.

proximately 0.1%, little or no increase in the oxygen bomb induction period is to be observed and storage tests indicate that no protection is obtained for the gasoline under storage conditionsu However, when used with an inhibitor,

a weight or a molal equivalent basis.

The following examples are given to illustrate the usefulness and practicability'of the process, but should not be construed as limiting it to the exact conditions or compounds given therein.

EXAMPLE 1 A Pennsylvania cracked gasoline was treated with a commercial gum inhibitor comprising N butyl aminophenol in 0.01% concentration. To the gasoline so inhibited was added 0.01% of various compounds representative of this invention. The oxygen bomb induction period of the gasoline was then determined. The results are shown in the following Table I.

Table I Compounds added (0.01%) Induction period Minutes Blank 05 +0.01% N-butyl aminophenol inhibitor 340 Diethylene triamine- 340 Triethylene tetramine. 600 Tetraethyiene pentamine. 605

, Table II P8151211;- Per cent of the diethylene triamlne added uty aminogg fg 0.000 0.001 0.002 0.003 0.004 0.005 0.006 0.008 0.010

mixture oi gum inhibitor and the diethylene triamine is more than equivalent to the combined weight of the two in the form of gum inhibitor alone.

Exnmnn 2 It will be observed that the A commercial gum inhibitor consisting of a fraction of wood tar distillate boiling within the range of approximately 240-280 C. was used in a Pennsylvania cracked gasoline with and without various quantities of added diethylene triamine which was chosen as being representative of the compounds of this invention. The original gasoline without added inhibitor had an induction period by the oxygen bomb method of 90 minutes. In Table III are shown the effects of the wood tar distillate inhibitor in concentrations of 0.01-0.06% with and without diethylene triamine in concentrations of 0.0001- 0.01%. It will be noted that the addition of as little as 0.0001% of the diethylene triamine to the gasoline inhibited with 0.04% wood tar inhibitor yields a gasoline of greater stability than can be obtained with 0.06% of the inhibitor alone.

Table III Per cent Per cent diethylene triamine added wood tar distillate inhibitor 0.000 0.0001 0.0003 0.0005 0.001 0.002 0.003 0.005 0.01

EXAMPLE 3 In the same gasoline used in Example 1 was added 2-t-butyl-4-methoxyphenol in amounts of 0.003-0.01% with and without diethylene triamine in amounts from 0.001-0.005%. The results obtained on the oxygen bomb induction period test are shown in the following table. In this case also the improved effect obtainable by the mixture is to be noted. Thus for example, with 0.001% of diethylene triamine, an induction period of 525 minutes is obtained when added to the gasoline inhibited with 0.01% of the inhib-v itor, while without the diethylene triamine an induction period of only 360 minutes is obtained.

Table IV Z-t-butyl Per cent diethylene triamlne 4-methoxyphenol, per cent 0.000 0.001 0.002 0.003 0.004 0.006

PPPPPPP? prevent depreciation thereof which comprises adding to said gasoline a gasoline gum inhibitor and a compound of the following general structure:

a R N-cHr-(cm).-N wherein R and R. are amino-alkyl groups and a: is an integer.

4. A process for treating cracked gasoline to prevent depreciation thereof which comprises adding to said gasoline a gasoline gum inhibitor and a minor quantity of diethylene triamine.

5. A process for treating cracked gasoline to prevent depreciation thereof which comprises adding thereto a gasoline gum inhibitor and an amount of an amino-alkyl-substituted alkylene diamine within the limits of approximately 0.0001-0.01% by weight of the gasoline.

6. A process for treating cracked gasoline to prevent depreciation thereof which comprises adding to said gasoline approximately 0.001-0.1% of a gasoline gum inhibitor and approximately 00001-00191, of an amino-alkyl-substituted alkylene diamine, both by weight of said gasoline.

7. A process for treating cracked gasoline to prevent depreciation thereof which comprises adding to said gasoline a gasoline gum inhibitor consisting of an N-substituted allryl aminophenol and an amino alkyl-substituted allrylene diaminet 8. A process for treating cracked gasoline to prevent depreciation thereof which comprises adding to said gasoline a gasoline gum inhibitor consisting of a woodvtar fraction boiling within the limits of approximately Mil-280 C. and an amino-alkyl-substituted alkylene diamine.

9. An inhibitor for cracked gasoline comprising essentially a mixture of a gasoline gum inhibitor and an amino-alkyl-substituted alkylene diamine.

10. An inhibitor for cracked gasoline which comprises essentially a mixture of an N-substituted alkyl amino-phenol with an amino-alkylsubstituted aikylene diamine.

11. An inhibitor for cracked gasoline which comprises essentially a mixture of a wood tar distillate gasoline gum inhibitor boiling within the range of approximately 240-280 C. and an amino-alkyl-substituted alkylene diamine.

12. A composition of matter useful for preventing the deterioration of oxidizable materials such as cracked gasoline which comprises a mixture of an antioxidant with a substituted alkylene diamine wherein the substituent group is an amino-allay] group.

13. In the art of stabilizing olefim'c distillates against deterioration by the addition of gum inhibitors thereto; the method of increasing the gum inhibiting potency of the inhibitor which adding to said gasoline a gasoline gum inhibitor and a minor quantity of triethylene tetramine.

16. A process for treating cracked gasoline to prevent depreciation thereof which comprises adding to said gasoline a gasoline gum inhibitor and a minor quantity of tetraethylene pentamine.

' JOSEPH A. CHENICEK. 

